#!/usr/bin/env python3
import argparse
import json
import logging
import requests
import shutil
import tempfile
import time
from subprocess import Popen, PIPE, TimeoutExpired
from typing import List, Optional, Tuple


parser = argparse.ArgumentParser()
parser.add_argument("--token", type=str, required=True, help="API token.")
parser.add_argument("--program", type=str, required=True, help="Program to run.")
parser.add_argument("--server", type=str, default="http://localhost:5000", help="Server address.")
parser.add_argument("--game", type=str, default="main", help="'main' or 'test_#'.")
parser.add_argument("--copy", default=False, action="store_true", help="Save a copy of the program to ensure the same code is used all the time.")
parser.add_argument("--log-level", type=str, default="warning", choices=["error", "warning", "info"])
parser.add_argument("--save-state", type=str, default=None, help="Save state to this file.")
# parser.add_argument("program", nargs=argparse.REMAINDER, help="Program to run.")


TIME_BEFORE_RETRY = 2.0
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger("client")


def main(args: argparse.Namespace) -> None:
    logger.setLevel(args.log_level.upper())
    program = args.program
    if args.copy:
        program = tempfile.mktemp()
        shutil.copyfile(args.program, program)
    program = "./" + program
    min_round = 0

    while True:
        state, wait_time = get_state(min_round, args)
        if state is None:
            # retry later
            time.sleep(wait_time)
            continue

        round = state["round"]
        min_round = round + 1
        # if requested, dump state to file instead
        if args.save_state is not None:
            with open(args.save_state, "w") as f:
                json.dump(state, f)
                return

        turn_json = run_subprocess(
            program, json.dumps(state), state["time_to_response"]
        )
        if turn_json is None:
            continue
        try:
            turn = json.loads(turn_json)
        except json.JSONDecodeError:
            logger.error(f"Invalid JSON returned by strategy code.")
            continue

        while not send_turn(turn, round, args):
            # if there was a connection error, retry later
            time.sleep(TIME_BEFORE_RETRY)


def run_subprocess(
        program: str, state_json: str, timeout: Optional[float]
    ) -> Optional[str]:
    """Run user program and return its output."""

    proc = Popen([program], encoding="utf-8",
                 stdin=PIPE, stdout=PIPE, stderr=PIPE)
    try:
        stdout, stderr = proc.communicate(input=state_json, timeout=timeout)
    except TimeoutExpired:
        proc.kill()
        logger.error("Strategy code took too long.")
        return None
    if stderr:
        logger.error(f"Strategy code stderr:\n{stderr}")
    if proc.returncode != 0:
        logger.error("Strategy code exited with non-zero exit code.")
        return None
    return stdout


def get_state(min_round: int, args) -> Tuple[Optional[dict], float]:
    """Get game data from the server.

    Returns None and wait time if there was an error."""

    try:
        r = requests.get(f"{args.server}/api/state", params={
            "game": args.game,
            "token": args.token,
            "min_round": min_round
        })
    # retry later if there was an error
    except requests.exceptions.RequestException as e:
        logger.warning(f"Request error: {e}")
        return None, TIME_BEFORE_RETRY
    if not r.ok:
        logger.warning(f"Server error: {r.status_code} {r.reason}")
        return None, TIME_BEFORE_RETRY

    state = r.json()
    # also retry if the server is not willing to give us the state yet
    if state["status"] == "waiting":
        logger.info("Server is busy.")
        return None, state["wait"]
    if state["status"] == "too_early":
        logger.info("Round didn't start yet.")
        return None, state["wait"]

    logger.info("Received new state.")
    return state, 0


def send_turn(turn: dict, round: int, args) -> bool:
    """Send turn to the server.

    Returns True if the server received the request."""

    try:
        r = requests.post(
            f"{args.server}/api/action",
            params={
                "game": args.game,
                "token": args.token,
                "round": round
            },
            json=turn
        )
    except requests.exceptions.RequestException as e:
        logger.warning(f"Request error: {e}")
        return False
    if not r.ok:
        logger.warning(f"Server error: {r.status_code} {r.reason}")
        return False

    # print errors
    # because such errors are caused by the submitted turn,
    # retrying will not help, so return True
    response = r.json()
    if response["status"] == "ok":
        logger.info("Turn accepted.")
    elif response["status"] == "too_late":
        logger.error("Turn submitted too late.")
    elif response["status"] == "error":
        logger.error(f"Turn error: {response['description']}")
    elif response["status"] == "warning":
        member_warns = [
            f"    {member['id']}: {member['description']}"
            for member in response["members"]
        ]
        logger.warn("Member warnings:\n" + "\n".join(member_warns))

    return True


if __name__ == "__main__":
    args = parser.parse_args()
    main(args)